Clinical audiologists at the VA Pittsburgh Healthcare System (VAPHS) have observed a substantive increase in the number of Veteran's presenting with self-reported hearing problems but who demonstrate normal or near normal hearing sensitivity when tested with a standard audiometric test battery. The primary complaint of these Veterans is difficulty hearing speech in background noise, and preliminary clinical data have suggested poor performance on some tests of central auditory processing. Moreover, when fitted with mild- gain open-fit hearing aids, which amplify the high-frequency part of the speech spectrum, these patients have reported a reduction in their hearing-related problems. Nearly all of these Veterans have reported histories of blast exposure and concussion while Operation Iraqi Freedom/Operation Enduring Freedom (OIF/OEF) deployed and described symptoms consistent with post-concussive syndrome. Similar auditory patterns for Veterans with mTBI have been reported by clinical audiologists from other VA medical centers and military facilities although the auditory problems of this group of Veterans have not been well described or studied (Fausti et al., 2009; Lew et al., 2007). This study was developed in response to the clinical complaints offered by these Veterans, with the goal being to better understand their problems by extensively assessing their auditory and auditory-related characteristics. A group of Veterans with histories of blast exposure, histories consistent with mTBI, and normal audiometric results, but notable auditory complaints will be evaluated with a standard audiometric test battery, health status and quality of life questionnaires, auditory physiological test procedures, and behavioral central auditory processing tests. We also will administer speech perception and psychoacoustic tasks, and verbal working memory and language processing tests to better understand various aspects of their ability to hear, remember, and process speech and language through audition. A reading test that parallels an auditory language-processing task also will be administered to determine if any identified language processing problems are limited to the auditory system. Comparisons will be made to a control group of Veterans who are negative for auditory and brain impairments, as well as to a group of Veterans with Post Traumatic Stress Disorder (PTSD) but without histories of blast exposure or brain injury. In addition, the influences of coexisting PTSD will be examined. Secondarily, the benefit of fitting this population of Veterans with mild-gain hearing aids that amplify the high-frequency part of the speech spectrum will be tested. The information obtained from this study will be a first step in elucidating the problems of these Veterans and will lay the groundwork for future studies that will focus on specific deficit mechanisms. This study also should contribute to the development of an effective assessment battery and interventions for this population.